A thrust bearing is used for minimizing axial movement of a crankshaft in an internal combustion engine. One option for lubricating the thrust bearing is to direct oil to the face of the thrust bearing, then allow the oil to drain freely from the bearing housing. It is possible to use a 360 degree thrust bearing, which traps oil emerging from the main bearing to lubricate the thrust bearing. However, this is a costly option and the lower 180 degree bearing associated with the main bearing cap does not provide significant thrust load support. It is also possible to provide pressurized oil to the upper thrust bearing, but this option is also more costly and requires additional block machining operations.
In conventional designs, it was possible to use 360 degree thrust bearings around crankshafts to supply an adequate amount of oil to the upper portion of the bearing. Oil emerging from the main bearing is trapped by the 360 degree thrust bearing, pressurized at the inner radius of the thrust bearing and flows radially outwardly through constant width grooves to the outer radius, providing lubrication supply to the thrust bearing. However, a 360 degree thrust bearing is a more costly option, and the lower portion of the bearing does not provide significant thrust support. FIG. 1 shows a 180 degree bearing assembly 150 of the prior art, in which oil from the main bearing 112 is not trapped by a lower bearing 110 and does not pressurize the inner radius of the upper thrust bearing 120. In this case, the upper bearing 120 is supplied by oil flowing by gravity into constant width grooves. Since the constant width grooves must be sufficiently large to direct gravity feed oil into the bearing 120 from the outer radial surface, oil is not significantly retained in the groove and does not adequately feed the bearing surfaces. It is also possible to provide pressurized oil directly from the oil rifle to the upper thrust bearing 120, but this option is also more costly, requiring additional block machining operations. Therefore, further improvements in this area are needed.